The use of external catheters for male urinary drainage systems is well known, as disclosed in U.S. Pat. Nos. 4,378,018, 4,187,851, 3,863,638 and 3,835,857. Essentially, such a system comprises an elastic sheath adapted to fit over the user's penis, the sheath having an outlet at its distal end connected to a tube leading to a suitable collection receptacle. The sheath includes a cylindrical body portion that fits over the penile shaft, a tapered neck portion that functions as a surge chamber near the distal end of the sheath, and a reduced drainage tube portion that extends beyond the neck portion. In a preferred construction, the sheath also includes an inner sleeve portion for sealingly (but non-adhesively) engaging the head or glans of the penis as disclosed in U.S. Pat. Nos. 4,581,026 and 4,626,250.
External catheters also quite commonly have an annular layer of pressure-sensitive adhesive on the inner surfaces of their cylindrical portions to retain the sheaths in place. Whether adhesive-coated or not, such catheters are usually marketed in rolled form with instructions that the sheaths be unrolled during application in essentially the same manner as a prophylactic condom.
Experience has revealed that such an application procedure is more difficult than it sounds. Orienting and unrolling a sheath with respect to a flaccid (and possibly retracted) penis is difficult even for a patient that retains manual dexterity and is capable of applying such a product to himself; it is obviously more difficult for a nurse or other attendant who lacks the tactile feedback that would assist a patient in carrying out the procedure on himself. The problems are compounded by the fact that a nurse undertaking such a procedure would normally wear surgical gloves and, should such gloves happen to contact the adhesive of the catheter as it is being unrolled, the gloves and catheter may adhere strongly to each other. Experience indicates that problems of applying such a catheter tend to be reduced if a nurse holds the penis in one hand and directs it into the opening of the rolled catheter held in the other, and then, immediately after commencing the unrolling operation, externally grips the sheath-covered glans and stretches or extends the penis as the unrolling operation is continued. It is believed, however, that nurses sometimes fail to perform such procedures completely, or with sufficient patience and care, because they are concerned about possible discomfort or injury to the patient, or are rushing to perform other healthcare duties, or simply because they find themselves uncomfortable making such direct and extended contact with the limp penis of an incontinent patient. Often the result is that such an external catheter is improperly or incompletely applied, causing discomfort and possible injury to the patient and resulting in leakage of urine when the drainage system is in use.
Other systems have been proposed in the past that utilize non-rolled sheaths and would not present the unrolling problems described above. Co-owned U.S. Pat. No. 4,540,409 discloses a catheter which has its cylindrical portion externally supported by a rigid and slightly tapered applicator tube. The neck and drainage tube portions of the catheter are reverted and extend through the interior of the tube. In applying the catheter, the entrance opening of the tube is directed towards the glans and the user grips the outlet tube section of the catheter to restrain that section, or even exerts a gentle pulling force, while at the same time urging the applicator tube in the direction of the penis. It has been found, however, that static friction between the applicator tube and the portion of the catheter stretch about it is not easily broken. Pushing the applicator tube more forcefully against the patient in order to overcome such frictional resistance may not only cause discomfort and possible injury to the patient but is unlikely to be effective because of the flaccidity of the target. Applying pulling force to the outlet tube portion of the catheter in an effort to break such static friction tends to have an opposite effect; the catheter simply stretches more tightly into engagement with the surfaces of the applicator tube at and about its entrance opening.
U.S. Pat. No. 4,840,187 discloses a sheath and applicator tube combination in which a liner casing of netting material is interposed between the tube and sheath to reduce static and sliding friction. The applicator tube is closed at one end and the netting is internally secured to the tube at that end. Inversion of the sheath is produced by pushing the sheath-covered open end of the applicator tube against the glans, although side window openings in the applicator tube do allow the user to grip and guide the distal portion of the penis (and the sheath liner casing covering it) into the interior of the tube.
British patent GB 2,120,102B discloses a more complex device in which an applicator tube is provided with a slidable internal tube 14 and a slidable external ring 15 connected to opposite ends of a woven liner. Use of the device is described as requiring the user to steady the penis with one hand while at the same time pulling draw pin 16 axially to shift the inner sliding tube 14 within support tube 11 to evert both the woven liner and the sheath carried by it.
While the use of a liner has been found to reduce static and sliding friction, those devices identified above which utilize such liners are still relatively complex in structure and operation and may be difficult to use effectively. In general, their recommended usage requires the operator to hold, grip, or guide the penis during sheath application, a contact that is often considered objectionable and may not produce the desired results.